Various fuels have been burned for some time to produce heat for various purposes including heating spaces that people occupy, such as within buildings. Combustion of fuels has produced various pollutants that have been released into the atmosphere, and alterations have been made to equipment to reduce the quantity of certain pollutants that have been emitted.
In various examples, natural gas and other fuels have been introduced into heat exchanger tubes in furnaces and burned as the fuel mixes with air. Such processes, however, have resulted in the production of a certain amount of oxides of Nitrogen (NOx) during the combustion process. It has been known for some time that NOx production can be reduced significantly by mixing air and fuel in advance of combustion and then burning a controlled and substantially homogeneous mixture of air and fuel. But premix burners have been plagued with noise resulting in oscillations of combustion and flow that have prevented premix burners from becoming workable in furnaces for occupied structures.
References that may provide useful background information include U.S. Pat. Nos. 5,971,745 (Bassett), 6,923,643 (Schultz), and 7,241,135 (Munsterhuis), as well as Demonstration of tricks and tools for solving self excited combustion oscillation problems, by Peter K. Blaade (NOISE-CON 2008, Jul. 28-30, 2008), and How to Solve Abnormal Combustion Noise Problems, by Peter K. Baade (SOUND AND VIBRATION/JULY 2004).
Needs or potential for benefit or improvement exist for burners, furnaces, and methods of making and controlling such apparatuses that reduce pollution (e.g., in comparison with alternative technologies), such as NOx emissions, from furnaces, for example, but that do not produce unacceptable levels of noise. Needs and potential for benefit or improvement also exist for burners, furnaces, and methods that do not require special installation procedures, that compensate for different elevations, and that compensate for different heating characteristics of the fuel. Needs or potential for benefit or improvement also exist for devices or apparatuses that produce less pollution than alternative burners, such as NOx emissions, for example, that are suitable for use in furnaces, HVAC systems, or HVAC units, for example that more-effectively avoid producing pollution (e.g., NOx emissions) that are inexpensive, that can be readily manufactured, that are easy to install, that are reliable, that have a long life, that are light weight, that are efficient, that can withstand extreme environmental conditions, or a combination thereof, as examples.
Needs or potential for benefit or improvement also exist for devices or apparatuses that reduce the production of pollution (e.g., in comparison with alternatives), such as NOx emissions, from furnaces, for example, that are quiet and that start reliably under a range of different conditions. In addition, needs or potential for benefit or improvement exist for furnaces and HVAC units that include such devices or apparatuses that reduce pollution, as well as buildings having such units, systems, devices, or apparatuses.
Further, needs or potential for benefit or improvement exist for methods of controlling, manufacturing, and distributing such furnaces, HVAC units, buildings, systems, devices, and apparatuses. Other needs or potential for benefit or improvement may also be described herein or known in the HVAC or pollution-control industries. Room for improvement exists over the prior art in these and other areas that may be apparent to a person of ordinary skill in the art having studied this document.
These drawings illustrate, among other things, examples of certain aspects of particular embodiments of the invention. Other embodiments may differ. Various embodiments may include aspects shown in the drawings, described in the specification, shown or described in other documents that are incorporated by reference, known in the art, or a combination thereof, as examples.